Two-lift door.



A. T. PRESCOTT..

TWO LIFT DOOR.

` APPLICATION FILED FEB. 2I. 19I6.

Patented July 18, 1916.

3 SHEETS-SHEET i IYJIIIIIIIJIlIlIIIYLII.lIllllIrllllIn-llllllllnhlllruq A. T, P-RESCOTT.

Tw`o LIFT DooR.' f

APPLICATION FILED FEB. 2l. 1916.

1,191,929. PatentedJuly 18, 1915 3 SHEETS-SHEET 2.

I sz l /0 T TUR/VE Y A. T. PRESCOTT.

TWO LIFT DOORl APPLICATION FILED FEB. zI. 191s.

PaIenIed July 18, .1916.

3 SHEETS-SHEET 3 earns PATENT Oruro ARTHUR T. PRESCOTT, OF EAST ORANGE, NEW JERSEY, ASSIGNOR TO GEORGE H. FROTHINGHAM COMPANY, OF NEW` YORK, N. Y., A CORPORATION 0F NEW YORK.

TWO-LIFT DOOR.

Specification of Letters Patent.

Patented July 1s, 1916.

Application filed February 21, 1916. Serial `No. 79,659.

of East Orange, county of Essex, and StateV of New Jersey, have invented certain new and useful Improvements in Two-Lift Doors, of which the following is a specification, reference being had to the accompanying drawings, forming a part thereof.

My invention relates to doors and particularly to heavy multi-section doors, such as are adapted for use in warehouses, factories, pier sheds, and -for like purposes.

One object of my invention is to provide an improved door of the aforesaid character having a simple and effective operating and counterweight equipment, whereby the weight of the door is substantially balanced in every position while it is being opened and closed. L

Other objects and advantages of my invention will be set forth hereinafter, and in order that my invention may be thoroughly understood I will now proceed to describe the same in the following specification and then point out the novel features thereof in appended claims.

Referring to the drawings: Figure 1 is a. front elevation of a door, arranged and equipped in accordance with my invention. Fig. 2 is a sectional elevation of the same door taken at right angles to Fig. 1. Fig. 3 corresponds to Fig. 2, except that the door is shown in its open instead of its closed position. Fig. 4 is a plan view of the door in its open position, showing a portion of the counterweight and operating mechanism of a second door adjacent to the rst. Fig. 5 is a sectional plan view showing a portion of the two door sections, overlapped and drawn to a larger scale. A modification of my invention is shown in Figs. 6 and 7 which correspond respectively to Figs. 2 and 3. Fig. 8 is a view corresponding to Fig. 5 but taken below the upper section of the door.

In the structure illustrated in Figs. 1 to 5 inclusive, 10 designates a pair of door posts door posts in a well knownmanner, and in guidewa ys 15 on the upper section.

0 Near the lower corners of the upper sectlon 12 are sheaves 16 and shown directly above these are stationary sheaves 17. The sheaves 16 are preferably located near the edge of the door section on which they are mountedand beyond the 'guideways l5 so that they do not interfere with the sliding movement of the lower section 14. The position of the sheaves 17 may of course-be varied Without changing the operation of the door. i

The operating and eounterweight mechanism comprises a shaft 18 on which is mounted a counterweight drum 19, pocket sheaves 20, and a gear wheel 21 a shaft 22 on which are guide sleeves 23, a countershaft 24. carrylng a sheave 25 for a hand chain 26, and interposed gears 27 between the gear wheel 21 and the countershaft 24.

The main counterweight 28 is suspended by a chain 29 from the counterweight sheave 19 which is specially formed to enable the counterweight to substantially balance the weight of the door in all intermediate positions as it is opened and closed. .This feature of my invention will be more fully explained hereinafter.

Suspended from the door hoisting chains 30 which extend over the pocket sheaves 2() 'are auxiliary counterweights 31. The chains lower door section 14, where they are attached to projections 32.

The shaft 22 and the sheaves 23 are spaced from the plane of the door opening a distance which. is about equal to the length of the upper door section. The projections 32, as clearly shown in Fig. 5, are of suiicient length to extend beyond the guideways 15 and into the planes of the sheaves 17 from which the chains 30 extend to the projecttions. AThe projections 32 in addition to serving as points of attachment for the chains 30, may also constitute stops and engage the supports for the sheaves 16 when the lower section has been elevated onto the upper section.

Before referring Ito kthe modification f shown in Figs. 6 and 7, the operation of the door already described, will be discussed.

' result effected will be the upward movement of the lower section 14 in the guideways 14 15. During this period the counterweights n are called upon to substantially belance the l from during weight of only the lower section. Accordingly, the counterweight sheave 19 from which the princi al counterweight 28 is suspended, is provided with a portion 35 of relatively small and substantially uniform diameter, the chain being unwouiid therethis initial movement of the lower door section.

If the hand chain is further actuated, the upper section 12, together with the lower section 14, is swung on its hinges 13 from itsinitial position to the position shown in Fig. 3. During this movement the pulley 16 acts as a point of attachment for the chain 30 since the projections 32 engage the supports for the sheaves 16 and no further relative movement of the lower section on the upper section is possible. The pull is therefore exerted directly from lthe shea-ve 16 'to the sheave 23 and the active weight which must be equalized by the counterweights, obviously increases gradually until the doors reach a substantially horizontal position as shown in Fig. 3. To compensate for this gradual increase in Weight and to insure the continued equalization of theweight of the doors, the sheave 19 is provided with a portion 36 which is frusto-conical, so that theeii'ect of. the coiinterweight 28, as the chain is unwound, gradually increases. While for simplicity I have shown the sheave 19 with smooth surfaces, it will iisiially be provided with a helical groove pocketed to receive the links of the chain 29.

The structure ofFigs. 6 and 7, to which reference may now be had, vcorresponds in most particulars to that already described, and like parts are designated by the same reference characters. The stationary sheaves 17 are, however, replaced by a pair of sheaves or rollers 40 located near the lower corners of the lower section 14. The chains 30 extend over the vsheaves 23, as in the previous arrangement; then around the sheaves 16, but instead of extending upwardly over the pulleys 17, they extend downwardly around the pulleys 40 and are attached at .their ends to projections 41 on 'the opposite side from the sheaves 16' and near the lower corners of the upper section 12. This arrangement has the advantage of shortening the chains 30. In operation this structure corresponds to that already described, the arrangement of the door sections, When the door is open, being clearly illustrated in Ijig. 7. i

Various modications' of the structures upon the upper,

illustrated may be effected within the spirit and scope of my invention, and l intend that only suoli limitations be imposed as are indicated in the appended claims.

What l claim is:

1.l A door comprising an upper section pivotally supported from above, a lower section adapted to slide upon the upper section, a exible hoisting member adapted to successively raise the lower section upon the upper section and swing the upper section about its pivotal support, and means on the upper section for guidin the iiexible member when the lower section is sliding said guide means constituting a point of attachment between the flexible member and the door while the upper section is being swung about its support.

2. A door comprising an upper section pivotally supported from above the door opening and having vertical guideways near its edges, a lower section adapted to slide in the guideways upon the upper section and having projections near its lower corners extending beyond the guideways and adapt- -ed to engage the lower end of the guideways when the doors are overlapped, guide pulleys on the upper section near its lower corners, and flexible hoisting members extending over the guide pulleys and attached to the aforesaid projections on the lower sections.

3. A door comprising an upper section pivotally supported from above the door opening and having vertical guideways near 1c@ its edges, a lower section adapted to slide in the guideways upon the upper section and having projections near its lower corners extending beyond the guideways and adapted to engage the lower end of the guidei ways when the doors are overlapped, guide pulleys on theaupper section near its lower corners, stationary guide sheaves above the door opening, and iexible hoisting members extending over the guide sheaves on no the upper section, .then over the stationary guide sheaves and secured to the projections of the lower section.

4. A. door comprising an upper section pivotally supported from above the door i opening and having guideways, a lower section adapted to slide in the guideways on the upper section, stationary guide pulleys above the door pivot, staionary guide pulleys spaced inwardly a distance substan- 112@ tiallyequal to the length of the pivotally supported door section, a guide pulley near the bottom of the upper section, a counterweight pulley, a counterweight, a flexible member extending from the counterweight over the counterweight' pulley, then over the spaced pulley, around the pulley on the upper door section and connected to exert a pull upon the lower section to cause it to slide upward on the upper section and upon iLSo -the upper section causing it to swingy inopening andA having guideways, a lower section adapted to slide in the guideways on the' upper section, stationary lguide pulleys 'above the door pivot, stationary guide pulleys spaced inwardly a distance substantially equalto the length of the pivoted' door section, a counterweight pulley, a counterweight,1a. flexible member extending from ithe. counteiweight over the counterweight pulley, then over the spaced pulley, around the pulley on the' upper door section, over the vstationary pulley above the door pivot and downwardly to connect with the bottom of the lower section;

6. A door comprising an upper section hinged near its upper edge above the door opening and having a guide member near its lower end, a lower section adapted to slide on the upper section and having a guide member near its lower end, a flexible member tending to open the door extending over the guide member on the upper section, under the guide member on the lower section, and connected to the lower end of the upper section.

7. A door comprising an upper section hinged near its upper edge above the door opening, a lower section adapted to slide upon the upper section, a guide sheave on the upper section, a guide sheave near the bottom of the lower section, a counterweight mechanism, and a flexible member connecting the counterweight mechanism and extending over the guide pulley of the upper section, around the guide pulley of the lower section, and connected at its end to the lower end of the upper section. y, f

SQA door comprising an upper section pivotally supported .from above the door opening, a lower section adaptedto slide upon the upper section, a guide sheave on the upper section, a guide sheave near the bottom .of the lower section, a counterweight mechanism comprlslng a sheave'havmg a cylindrical portion and an 'adjacent fru'stoconical portionv of increasingv diameter, a fixed pulley spaced from the counterweight mechanism in thedirection in Iwhich the door is adapted to swing, and a flexible member extending from the counterweight mechanism over the fixed ypulley around the guide pulley on the upper section, under the guide pulley of the lower section, and connected at its end to the lower end of the upper section. Y

9.1A door comprising an upper door section pivotally supported from above the door opening, a lower section adapted to slide upon the upper section Iand having a guide member near its lower end, a counterweight mechanism, a fixed pulley spaced from the counterweight mechanism in the direction in which the door swings, and a flexible member extending from the counterweight mechanism, over the ixedv pulley, under the guide member of the lower section, and connected at its end to the lower end of the upper section.

In witness whereof, I Vhave hereunto set my hand this 12th day of February, 1916.

ARTHUR T. PRE-SCOTT, 

